A semiconductor device is mounted with a semiconductor element that is a heating component. The semiconductor element dissipates heat in the case of driving the semiconductor device and becomes a high temperature. In order to enhance heat dissipation properties of the semiconductor device, a thick metal substrate or ceramic substrate, provided with a circuit pattern is used for a substrate that fixes the semiconductor element. There is also known a configuration in which a fin base formed with heat dissipation fins is screwed to be joined to a metal substrate and the heat dissipation area of the substrate is enlarged. A silicon-based resin material with insulation properties like grease intervenes between the fin base and the metal substrate.
A power semiconductor device having such a configuration needs to have a process of applying a silicon-based resin material on the front of the metal substrate, the ceramic substrate, or a heat dissipating member. Use of the silicon-based resin material makes the number of manufacturing processes increase and further makes heat dissipation properties deteriorate.
There is known, for example, Patent Document 1 as a technique in which a resin material is not made to intervene. In this case, a ceramic substrate is mounted on a metal substrate with fins. The whole of a semiconductor device is sealed with an epoxy resin. Patent Document 2 deals with a technique characterized by a method of manufacturing fins.